shift in the wake of the arrest of the evidence trying to be hit by students in this ce and katherine harris has the report. >> one day after homeland security officials confirmed that a student from caused exxon was charged with destroying evidence in the boston marathon investigation a major security changes ordered at the borders. effective immediately customs agents musterify every four students entering u.s. has a valid student to be separate and he withdrew from class's january 4th and re-entered into weeks later because customs was never notified of the change former homeland security officials said policing a student visa within 500,000 issued in 2012 as a chronic problem. >> the customs border says your visa is expired but then who enforces it? boston says a must be better cooperation is there if they believed the bombs made in the tamerlan tsarnaev home now investigations are intensifying on his widow catherine russell spinach she might not have nobody raises the question as to what did she know? what was their relationship at the time? >> to sources familiar tell fox news she comm